The invention relates to an associative memory device with optimized occupation, particularly for the recognition of words.
As is known, for reading text, particularly handwritten text, various character recognition systems have been developed, based on text segmentation to separate the individual characters or portions thereof one from another, and on processing of the segments obtained to identify the characters. This procedure outputs a series of characters including spaces and punctuation marks.
Current systems are not, however, always capable of outputting correct data because of the presence of noise, the particular graphical characteristics of the text or the limited capacities of the recognition system. Consequently, further processing of the characters is necessary so as to guarantee the correctness of the sequence of characters and the extraction of meaningful words.
For these reasons, word recognition devices have been proposed which compare an input word to be recognized with a plurality of words belonging to a vocabulary, until a word in the vocabulary is identical to or nearest to that to be recognized is identified. The comparison procedure, carried out sequentially on the words in the vocabulary, does, however, require a considerable amount of time.
To solve this problem, in a patent application filed by the applicant on the same date, use is proposed of an associative memory, in which the word to be recognized is compared in parallel with all the stored words, enabling search times to be considerably reduced and hence permitting effective use in a word recognition device.
In currently used associative memories, data are stored by lines, or each line (each row for example) is intended for the storage of a single datum. For word recognition, however, given that the words belonging to a vocabulary have different length, the problem of optimizing memory contents so as to be able to store a sufficient number of words in a memory of modest size exists. Furthermore, the words must be easily searchable for comparison to the input word.
An object of the invention is to provide an associative memory, the organization of which is such as to improve optimization of memory occupation, improving extractability of stored data therefrom.
In general terms, the problem may be formulated as follows: given an associative memory of size Mxc3x97N, containing M vectors of size N, given a database of Z vectors (where Z greater than M) of dimensions which are not constant but all less than N, the problem is that of organizing the associative memory in such a way as to store this database in the associative memory, optimizing its use.
In a first embodiment, the present invention includes a method having steps of parsing input data to provide a portion delimited by predetermined characteristics and determining a length of the portion. The method also includes steps of comparing the length to a table of lengths of data stored in an associative memory and providing the portion to a section of the associative memory containing data having lengths comparable to the portion. The method further includes steps of identifying a closest match between a datum stored in the section and the portion and storing an address from the associative memory corresponding to the datum in a second memory.
In a second embodiment, the invention includes a method having steps of parsing a dataset comprising sequences of analog values to determine lengths associated with each datum of the dataset, collecting data from the dataset having comparable lengths into groups and writing each group of the groups of data to a separate section of an associative analog memory.